— By Christopher Collins, AIA, NCARB —
The good, the bad & the ventless …exhaust hoods.
The look of dismay on the chef’s face told me everything I needed to know: the vent hood was not cutting it and big money was going to be burned trying to remedy his woes. The issue was the ventless hood that was used for the cooking appliances. And not really the exhaust type that was being employed, but more of the expectations around that piece of equipment. That’s when I realized what ventless was suffering from — misunderstood marketing and bad kitchen design.
What is a Ventless Exhaust Hood, Anyway?
No, it’s not an oxymoron. Ventless exhaust or ventless hoods are, in essence, an internal filtering hood system to scrub cooking exhaust air. This means it scrubs the air before putting it back in the same room rather than venting to the outside like a traditional Type 1 kitchen hood. But, unlike a traditional hood with a roof mounted fan that exhausts grease laden air to the outside world, vent-free hoods clean the grease laden air in place and recirculate air back into the space — hence, ventless.
Pro:
Eliminates the need for grease duct, chases and fans to exhaust air outside the building. You also don’t have to introduce make-up air to replace exhausted air with a ventless hood.
This is a critical point to understand since viewing a hood as exhaust versus a scrubber can ruin your perception of a perfectly good piece of equipment. Understanding this delineation might clear up some of the confusion that stems from the sales and marketing material for these products.
Con:
If eliminating a traditional hood is all you focused on, you may be disappointed with your results…read on!
Get the HVAC Out of Here
Pick up any marketing slick about ventless hoods and you might think this technology was perfect for any situation, anytime, anywhere. Ventless hoods use a triple filtration approach, a baffled grease filter, a HEPA or charcoal filter and finally a paper filter. But that’s where these things get a bad rap. Grease laden air is filtered, and if an additional charcoal filter is used, some cooking odors are removed as well. Now consider the amount of heat that your cooking appliances generate. By definition, ventless means no true venting, so no removal of heated air or, in some cases, cooking odors.
It bears noting that there are many manufacturers out there that are implementing integral hoods with their specific pieces of equipment. This could be a pizza oven, small fryer, induction burners, bakery ovens, etc. While they have specifically solved the issue of venting, similar to non equipment specific ventless hoods, it’s up to the designer or engineer to deal with additional heat and odors.
Con:
The ventless air is diverted immediately back into the room, so the majority of odors and heat gained from cooking appliances will not be removed.
Knowing the where and when of vent-free can go a long way to dispel myths and misunderstandings that surround this equipment. While it is true that a traditional hood is no longer needed with this solution, additional engineering design to ensure staff comfort is very much needed. In fact, remember that kitchen at the beginning of the article? We solved their issue by supplementing their vent-free equipment with additional cooling air with non rated exhaust ductwork to remove odors. Now they love it.
Pro:
Ventless hoods can be accommodated by increasing airflow from existing HVAC system capacity and providing supplemental exhaust.
Right Place, Right Time
Another advantage that ventless hoods offer is “flexibility.” Not that you can pack it up and take it with you; flexibility comes in the form of placing a hood wherever you wish, since an exhaust pathway is not required.
Pro:
Ability to work in a cooking appliance in a space that wouldn’t be feasible otherwise.
The tradeoff for this portability, however, is capacity and in maintenance. Ventless hoods are currently limited in size per unit, typically a 48-inch width and equipment must be electric as gas appliances require combustion air to be externally exhausted. Maintenance for the triple filtration system is also a key factor as the unit’s safety features will shut it down if not properly maintained.
Con:
Ventless exhaust is not as forgiving as a traditional exhaust system; a shutdown during service hours can be disastrous to your bottom line!
So, Is Ventless Right for Your Kitchen?
Now that you know some of the pros and cons, you can at least approach ventless hoods without all the marketing hype, and apply it to your unique situation.
So, consider ventless hoods as you would any other equipment in the kitchen. It has its time and place. If you are using it where it makes sense and have incorporated it as an engineering solution — and are keeping it well maintained — then it will serve you well and can add just as much value to your kitchen as any other piece of equipment. If you have questions or a situation you’d like to review — reach out to us! n
— Christopher Collins, AIA, NCARB is a principal with Nvironment, a creative design and architecture firm located in Columbus, Ohio.